1. Field of the Invention
The invention relates generally to powered surgical instruments. More particularly, the invention relates to high speed electrically operated surgical instruments such as drills, etc. and devices for cooling such instruments.
2. Description of the Prior Art
The use of high speed electric motors in handpieces in medical applications raises a concern for controlling the temperature of the handheld devices operated by these motors. The present invention is directed to maintaining the temperature of such devices within acceptable limits by using cooling fluid.
High speed electric motors are known to be used in surgical orthopedic applications but, because they are generally used for shorter surgical procedures, temperature buildup has not been a significant issue. High speed motors intended to be used for extended periods of time are currently powered by pneumatic means because the expansion of gases used to drive these motors provides cooling to maintain the handheld device at acceptable temperatures.
Device size and logistical constraints (e.g. availability of fluids to power pneumatic devices) have created a need for the use of smaller, more practical electric devices rather than pneumatic devices. While the necessity to control the temperature of these devices is the subject of this invention, an added feature is that the fluid used to cool the motor may also be used to irrigate the surgical site, thereby eliminating the need for a separate irrigation source.
Additionally, in surgical procedures performed with handheld powered instruments it is necessary to sterilize the instruments prior to use. Therefore, in order to enable a high speed electric handpiece to be used, the handpiece must be provided with a cooling mechanism which does not compromise the sterilizability of the instrument. Some prior art dental device patents are known which are related to this problem, but the devices taught by these patents may be difficult to clean and sterilize.
The use of cooling water is shown in U.S. Pat. No. 3,324,552 (Saffir) in a dental handpiece having a removable electric motor. The water is circulated in a chamber around the outside of the motor and may be partially directed to flush the area of the tooth being drilled or cool the burr or other tool being used. However, the Saffir device may be difficult to clean and since surgical handpieces must be sterilized after use, it would be preferable to be able to detach and discard any coolant tubing prior to cleaning and sterilizing the handpiece.
U.S. Pat. No. 4,184,256 (Loge et al.)shows a dental handpiece having a coolant line in the motor thereof and U.S. Pat. No. 4,107,846 (Fleer et al.) shows a dental handpiece having a flexible hose which may be plugged into a pair of conduits to direct coolant to the dental tool being use. However, no known prior art shows a surgical handpiece adapted to be cooled via a disposable tubing set easily attachable to the handpiece.
It is according an object of this invention to provide a surgical handpiece which may be cooled by circulating fluid.
It is also an object of this invention to provide a fluid cooled surgical handpiece operable with a tubing set which may be discarded after a single use.
It is another object of this invention to provide such a fluid cooled surgical handpiece with a tubing set having a cassette which facilitates selective attachment of the tubing set to the handpiece.